The best cue is to keep your shoulder blades back and down. The first few reps show the incorrect position. In the last few reps, the shoulder are back and down.
For any horizontal pulling exercise, like seated cable rows, keeping the shoulders back and down will ensure your lats and mid back are being hit the hardest, instead of just the upper traps and biceps.
In the video, the first couple of reps are performed incorrectly and the last couple of reps are performed with the shoulders back and down.
About 2 years ago, we asked one of our resident nutrition and supplement gurus, John Berardi, to give us a peek into his training journal. While best known for dispersing dietary dogma, JB has built a rock-solid physique from countless hours of fraternizing with heavy dumbbells and barbells.
Start your biceps work with hammer curls, then a preacher curl variation like the one here. For safety, finish with heavy barbell curls when you're biceps are fully pumped.